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Full text of "Treatise On Applied Analytical Chemistry(Vol-1)"

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and impurities, up to i% ; D =0-920-0-924 ; iodine number = 100-114 '
Maumene number (Tortelli) =71-3°; solidifying point of the fatty acids =

Vegetable Fats

These are fatty substances of vegetable origin and solid at the ordinary
temperature. Among them are also some so-called Vegetable waxes, such
as Japan wax and myrtle wax, which are, however, not true waxes but solid
fats, sincejthey are composed of glyceryl esters and not esters of higher
alcohols.1 jsTrue waxes of vegetable origin include only carnauba wax and
a few others (see Waxes).

The more important vegetable fats are those of cacao, coco-nut, palm
and palm-kernel, vegetable tallow and a few others which are described ;
their characters are given in Table XLV, together with those of other
vegetable fats of some interest.

(Cocoa Butter)

From the seeds of Theobroma cacao, is a somewhat brittle, yellowish-
white solid with a taste and smell recalling those of torrefied cacao. It
dissolves in 5 parts of boiling absolute alcohol and is almost insoluble in
90% alcohol; it is soluble in 3 parts of ether. It does not readily turn
rancid, and only when very old or badly stored does it contain more than
i% of free acid (calculated as oleic acid) ; the rancid fat is white. Fat
from the skins of cacao seeds is, however, markedly acid even when fresh.
The characters of the fat are given in Table XLV.

Detection of Adulterations.—It may be adulterated with coco-nut
butter, tallow, stearine, solid paraffin and wax, or, more rarely, with other
vegetable fats (Japan wax, Dika oil), almond oil, hazelnut oil or other seed
oils. Such adulterations are detected by determining the different char-
acters of the fat, bearing in mind the following:

Coco-nut oil raises the saponification number and the volatile acid
number, but lowers the iodine number and the refractometric reading.
Stearine raises the acid number and lowers the iodine number, and is, more-
over, easily detectable by its ready solubility in alcohol. Solid paraffin
and wax lower the saponification number and the iodine number and may
be recognised in the unsaponifiable portion. Vegetable oils in general lower
the specific gravity and the melting point and raise the iodine number and
the refractometric reading. Japan wax increases the density, the acid
number and the saponification number and lowers the iodine number. Dika
oil raises the saponification number and the refractometric value and lowers
the iodine number (see Table XLV). Tallow is not easily detectable by
physical and chemical characters alone, but its presence may be shown
by the cholesterol test (see Lard).

i These vegetable waxes are distinguishable from true waxes in that they are com-
pletely saponified by alcoholic potash, yielding soaps entirely soluble in water.e investiga-